68 camaro rs wheel question

[Heavyonthegas]

Little help here. trying to figure out back spacing for my 68 camaro rs. I mini tubbed the rear with a ridetech 4 link and used there narrowed rear end (54.75) with wilwood brakes. My measurements are 7 5/8” from fender lip to wms and 6 3/8” from wms to inside of wheel tub. I plan on running a 18 x 11 with 315/30 for the rear.. I came up with 5.25 but not sure if that’s right?

For the front i have tubular controller arms (not sure brand got them from a friend who had them laying around) with ridetech tall spindles and wilwood dynapro 6 piston brakes 12.19” rotors Viking coilover’s I don’t have the front clip on yet but would 245/40/18 on 18 x 8 with 4.875 bs be a safe bet or should I wait till I have the front clip back on to measure?



this is my first endeavor in the car building process so any help is much appreciated
thanks kevin